New home internet modem won’t connect with son’s school laptop

This summer we swapped out and got a new internet modem, it's the big white box one. Everything in our house can connect via WiFi, smart tv's, my laptop, multiple Alexa devices, printer, and 2 other laptops plus our mobile phones. My son's high school issued laptop will not connect. But it connects to my brother's WiFi at his house with Spectrum and he can use it at school with their WiFi. His friend has brought his school laptop too and it won't connect. Our network ID shows up in the available WiFi options and he can click on it and type in our network key/password and it shows connected but no websites will load through Chrome or Edge. Can't open his Google docs or even www.google.com. Please help. He needs to be able to do his homework at home because everything nowadays is digital.